Procedure for removing and replacing the Battery Junction Box on a 2023 Rivian EDV 500, which manages high-voltage battery distribution and requires complete HV system isolation.

Warnings

Tools required

Parts

• Battery Junction Box assembly × 1 — Use OEM specification
• High-voltage connector seals × 4 — Use OEM specification
• Junction box mounting hardware kit × 1 — Use OEM specification
• HV interlock connector × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake. Place wheel chocks at all four wheels
2. Ensure vehicle has been off for minimum 10 minutes before beginning procedure
3. Don high-voltage safety equipment including Class 0 gloves and face shield
4. Connect Rivian diagnostic software to vehicle and document any stored DTCs
5. Access underbody by raising vehicle on lift to comfortable working height
6. Remove belly pan and underbody protective panels to access battery pack area
7. Locate Battery Junction Box on forward section of battery pack assembly
8. Photograph all cable routing and connections before disassembly for reference

Procedure

1. 1

   Disable high-voltage system
   Using Rivian diagnostic software, command the vehicle into Service Mode to open all HV contactors. Verify Service Mode is active on instrument cluster display. Confirm all propulsion and charging functions are disabled.
2. 2

   Disconnect 12V battery
   Open frunk and disconnect negative terminal of 12V auxiliary battery. Wait 2 minutes for all modules to power down completely. Isolate negative cable to prevent reconnection during service.
3. 3

   Remove HV service disconnect
   Locate HV service disconnect plug on top of battery pack near driver side. Pull service disconnect handle upward and rotate counterclockwise to remove. Store disconnect plug in secure location away from work area. Wait mandatory 15 minutes for HV capacitor discharge.
4. 4

   Verify zero voltage
   Using calibrated HV multimeter, test for voltage at Battery Junction Box main terminals. Verify reading is 0V DC between positive and negative bus bars. Test between each HV terminal and vehicle ground. Document all voltage readings below 5V DC before proceeding.
5. 5

   Disconnect HV interlock circuit
   Locate orange HV interlock connector on Battery Junction Box cover. Depress locking tab and carefully disconnect interlock plug. Inspect connector pins for corrosion or damage. Set connector aside with protective cover in place.
6. 6

   Remove low-voltage connections
   Disconnect all 12V control harness connectors from Battery Junction Box. These include battery management system communications, temperature sensors, and contactor control circuits. Label each connector with tape for reassembly identification.
7. 7

   Remove junction box cover
   Remove fasteners securing aluminum cover over Battery Junction Box using appropriate socket. Lift cover carefully and inspect internal gasket condition. Check for any signs of moisture intrusion, corrosion, or thermal damage on internal components.
8. 8

   Disconnect main HV bus bars
   Using insulated tools, remove bus bar mounting bolts connecting Battery Junction Box to pack positive and negative terminals. Work on one connection at a time. Place insulating barriers over exposed terminals immediately after disconnection. Note orientation and position of each bus bar connection.
9. 9

   Disconnect individual cell module connections
   Remove HV cable connections from junction box to individual battery modules. Each connection has spring-loaded safety locks that must be depressed before removal. Support cable weight during disconnection to prevent strain on terminals. Cap all exposed HV terminals with insulating covers.
10. 10

    Remove coolant line connections
    The Battery Junction Box has integrated cooling passages. Disconnect coolant quick-connect fittings at inlet and outlet ports. Have drain pan ready as residual EV Battery/Motor Coolant will drain from lines. Plug coolant ports to prevent contamination.
11. 11

    Remove junction box mounting fasteners
    Remove all mounting bolts securing Battery Junction Box to battery pack housing. These typically include perimeter mounting points and central support brackets. Note different bolt lengths and positions for proper reassembly sequence.
12. 12

    Extract Battery Junction Box
    Carefully lift Battery Junction Box assembly from battery pack. Unit weighs approximately 25-30 lbs. Ensure all electrical connections and coolant lines are fully disconnected before lifting. Place removed junction box on clean, non-conductive surface for inspection or replacement.
13. 13

    Prepare mounting surface
    Clean battery pack mounting surface where junction box seats using non-conductive brush. Remove any debris, old gasket material, or corrosion. Inspect mounting bosses for thread damage. Apply thin coat of dielectric grease to mounting points to prevent galvanic corrosion.
14. 14

    Install new Battery Junction Box
    Position new or replacement Battery Junction Box into battery pack cavity, aligning mounting holes and coolant port locations. Ensure junction box thermal interface pad makes proper contact with pack cooling surface. Install mounting fasteners hand-tight initially, then torque in star pattern to ensure even seating.
15. 15

    Reconnect coolant lines
    Connect coolant supply and return lines to junction box ports. Push quick-connect fittings until audible click is heard. Verify connection security by pulling on lines. Wipe any spilled coolant from surrounding components.
16. 16

    Reconnect HV connections
    Reconnect all HV cables and bus bars to Battery Junction Box in reverse order of removal. Apply anti-oxidant compound to all copper contact surfaces before connection. Torque all HV terminal fasteners per service specifications. Verify each connection is tight and properly seated with no visible gaps.
17. 17

    Install junction box cover
    Install new gasket on junction box cover if required. Position cover over junction box and install fasteners. Torque cover bolts in cross pattern to ensure even gasket compression and proper seal against moisture intrusion.
18. 18

    Reconnect control circuits
    Reconnect all 12V control harness connectors to Battery Junction Box following labels from disassembly. Ensure each connector locks securely with audible click. Reconnect HV interlock circuit connector last, verifying proper pin alignment.

Reassembly

1. Reinstall all underbody protective panels and belly pan removed during access
2. Reconnect 12V auxiliary battery negative terminal
3. Reinstall HV service disconnect plug - rotate clockwise until fully seated and locked
4. Using diagnostic software, exit Service Mode and command HV system to ready state
5. Verify all fasteners are properly torqued and no tools remain in work area
6. Check that all HV covers and protective barriers are properly installed

Verification

• Using Rivian diagnostic software, verify Battery Junction Box communication on vehicle network without fault codes
• Confirm HV system voltage matches expected pack voltage (typically 350-420V depending on state of charge)
• Perform HV isolation test using diagnostic software - verify isolation resistance exceeds 500 ohms/volt minimum threshold
• Check for any coolant leaks at junction box connections with system pressurized
• Verify all HV interlock circuit integrity - should show proper continuity when connected
• Test drive vehicle to confirm normal propulsion operation and charging capability
• Monitor battery temperatures during initial operation to verify proper cooling function
• Verify no new DTCs are present after repair completion and test drive

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